Refrigerating apparatus



April 29, 1941; N, SMITH 2,240,354

REFRIGERAT ING APPARATUS Original Filed March 29, 1935 ATTORNEYSPatented Apr. 29, 1941 REFRIGERATING APPARATUS Nelson J. Smith, Dayton,Ohio, assignor to General Motors Corporation, Dayton, Ohio, acorporation of Delaware Application March 29, 1935, Serial No. 13,711Renewed November 2, 1939 9 Claims.

This invention relates to refrigerating apparatus and more particularlyto air conditioning apparatus and controls for air conditioningapparatus. I

Heretofore, air conditioning apparatus has in some cases been providedwith a manual control for controlling the admittance of outside air tothe air conditioning apparatus and in other cases has been provided withan automatic control. Neither of these controls arealtogether'satisfactory under'all conditions, since the manual airconditioning system with a combined automatic and manual control whichwill control the entranceiof external air and yet'has automatic controlswhich will properlytake care of operations in case the proper operationof the manual control is neglected.

It is another object of my invention to provide a combined manual andautomatic control for an air conditioning system which controls both thesupply of external air and the recirculation of room air through the airconditioning unit.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing wherein'a preferred form of the present invention is'clearlyshown.

In the drawing,' ,the figure is a diagrammatic representation of anairconditioning unit and control system embodying my invention.

In my disclosureJ have disclosed an air conditioning unit containing arefrigerating system for cooling and dehumidifying air, as well as asteam coil with a humidifying devicefor heating and humidifying the airtogether with a source'of" pressor 32 driven by an electric motor 34 forcompressing the refrigerantand for forwarding the compressed refrigerantto a water cooled condenser 36 where the condensed refrigerant isliquefied and collected in a receiver 38.

In order to cool the condenser and the compressor compartment 22, thereis provided a source of water which is conducted through the pipe 40under the control of a valve 42. The pipe 40 extends into thecompartment 22 and is provided with a serpentine coil 44 for absorbingheat from the compressor compartment. The water, after passing throughthe coil 44, extends through the pipe 46 to the lower portion of thecondenser 36. The condenser 36 is preferably of the double tube type inwhich the refrigerant passes through the inner tube in one direction,

that is downwardly, and the water flows through the space between theinner and outer tubes in the opposite direction, that is upwardly, so asto secure the thermal advantages of the counterfiow method of cooling.The water passes through the condenser 36 in a direction opposite thatof the'refrigerant and then is discharged through the pipe 48 to adrain. The flow of water is preferably controlled by. an automatic valve50 according to the pressure within the valve chamber of the compressor.

Within the chamber or coil compartment 24 there is provided a solenoidvalve 52 which is controlled by an electric circuit (not shown) andexternal or outside air'and a source of room air which is controlled bya damper capable of being operated manually but also having automaticcontrols which will shut off the flow of outside air into the unit whenthe external temperature is rather low and/or whichwill also shut offthe outside air when the steanrcoil'is not in use.

This control thus prevents the Lentrance of too 1 conducting room airtothe coil'compartment'and a controlmeans 30. Within the compressorconipartment 22 there is provided a refrigerant coma thermostatic valve54 controlled by the thermostat 56 which controls the flow ofliquidrefrigsteam coil '62 for heating the coil within the 4 compartment which"is supplied with steam through the pipe 64 underthe control of a handvalve 65, an automatic valve 68 and a valve 10 provided with a remoteinanual control 12 which extends to the outside of the compartment 24.

The valves 66, 68 and ll] control the flow of steam through the steamcoil '62 where the'steam condenses and gives off heat to the air withinthe compartment 24 and the condensed steam is discharged througha'discharge pipe 14. The air is humidified by fine sprays or drops ofwater which drip over'the steam coil. This is provided by a-pipe 16which connects with the water pipe 40 and this flow of water iscontrolled by three -manually adjustable sight glass water valvesdesignated by the reference character 18, each of which permitsa finestream of water to now through the connecting pipes and 8| to aperforated pipe 84 which permits the water to be sprayed or dripped ontothe steam coil 62 to cause its vaporization. .Any water or moisturewhich may drip from the steam coil 82 or which may drip from theevaporator 58 is collected by the large fiat pan 88 located in the lowerportion of the compartment 24 and provided with a drain 88 for carryingaway the drip. Within the compartment 24, there is also provided anelectric motor 90 having a centrifugal fan 92 at each end which draw inair either through the external air duct 26 or the room air duct 28 overthe surfaces of the coils 58 and 62 and discharges the air through theoutlets 94 and into the room.

An opening is provided within the side wall of the compartment 24 andcooperating with this opening is a damper 96 which is provided with agear 98 which meshes with a segment I02 pivoted at I04 which is employedfor moving the damper into its upper position where the external oroutside air is cut off and room air flows into the compartment-24 or tothe lower position as shown in the drawing where the room air is cut offand external or outside air is permitted to be drawn into thecompartment 24. In order to manually operate this damper, I haveprovided a link I04 having a hook-shaped upper end I06 which is held bya rather Weak spring I08 against the wall III) of the'spring cavitywhich is formed within the lower end of a manually adjustable slidablemember II2 which is provided with an adjusting nut and knob II4 whichmay be used to move the slidable member I I 2 in either direction but islimited by the slot H6 in its movement. The knob H4 is also used tofasten the slidable member I I2 at any point in the slot I I6.

With this arrangement, the member IIZ may be moved downwardly toforceably move the damper 98 to its upper position in which the externalor outside air coming through the outside duct 26 is cut off andprevented from entering the chamber 24. This control member II2 may alsobe moved upwardly to move the damper 95 to its downward position asshown in the figure whereby the external air is permitted to flow fromthe "duct 26 'to the compartment 24 while room air is cut off. Thiscontrol member IIIZ may also be moved to intermediate positions andlocked by the knob II4 so that some room air may be recirculated whilesome outside air may also be drawn in. It should be noted that all thatholds the damper 96 in. its lower position as shown in the fi ure to cutoff the room air and permit the entrance of outside air is the springThe damper 98 is normallyin a position to shut off the room air and topermit the entrance of the outside air during the summer, spring andfall when the air is comparatively mild, such as around 60 F. Under suchconditions, a considerable amount of air is drawn into the room when thefan 92 is in operation and so provides a supply of fresh air which iswarmed and humidified by the steam coil 52 before it is discharged intothe room. It has been found, however, that when the temperature of theoutside air is slightly below freezing, and the steam coil is shut offthat up and that the room may become excessively cooled. When theweather becomes moderately cool outside, such as50 'F. or below, and theheating has been shut off in the building, there I is also the dangerthat too much cold air will enter the room and the temperature of theroom to which the air conditioner supplies its air will becomeexcessively cold should the damper remain open under such conditions.

In order to overcome or prevent these possibilities, I have provided anautomatic means which will function to prevent the freezing of the steamcoil and to prevent the room from becoming too cold. In order to dothis, I provide a thermostat I I8 in heat exchange relation with somesuitable portion of the steam coil 62 which is connected by a tube I20to a bellows I22 which is connected to the segment gear I02. By thisthermostat II8, when the steam coil is on, the bellows I22 will beexpanded to tend to keep the damper in its lowermost position where theair from the room is cut oil. This thermostatic bulb II8'is preferablyfilled withsome suitable volatile liquid such as methyl or ethyl alcoholwhich will only be effective at temperatures above a relatively hightemperature such as F. When the steam coil 62 is comparatively cold, thevolatile liquid within the thermostat II8 will contract, thus collapsingthe bellows I22 and causing the segment gear I 02 to be pulleddownwardly by a control spring I24 which is provided with a screwthreaded adjustment I26 for varying its temperature. The spring I24 issufliciently stronger than the spring I08 to overcome the force of thespring N8 in order to move the damper 96 from its lower position asshown in the figure to its uppermost position as shown where it will cutoff the external or outside air.

Likewise, in order to prevent the entrance .of external air when theweather outside is 50 F. or below for preventing the room from becomingtoo cold, I provide a second thermostat I28 located within the outsideair duct 26 which is connected by a tube I30 to a second bellows I32which in turn is also connected to the se ment gear I 02. Preferably,the thermostat I28 is provided with a volatile liquid which will beineifective at temperatures above 50 F. but which will at lowertemperatures allow the bellows I32 to collapse under the'influence ofthe spring I24 and move the segment gear I02 downwardly against thetension of the spring I08 in order to move the damper 96 upwardly toclose the outside air inlet in the event that no heat is supplied to theheating coil 62 to prevent the room from becoming too cold. When thereis steam in the coil 62, the thermostat H8 and the bellows I22 willprevent the collapsing of the bellows I32 by the spring I24.

Thus, in either case I have provided means for overcoming the manualsetting when the steam coil has been turned off or when the outside. airis too cold in order to prevent the freezing of the coil and to preventthe room from becoming too cold. This, of course, is permitted byproviding a resilient connection which includes the spring I08, whichcan be overcome to permit the movement of the damper 96 despite theposition of the manual control II2. Thus, my manual control is effectiveat all times except when the outside air temperature is too cold or whenno steam is passing through the steam coil. The automatic control canalways be overcome to close the outside. air and the manual control isalso capable of shutting off the room air and permitting the entrance ofoutside air except under the conditions when it would be;

undesirable to do so. Thus, I have provided a control for an airconditioning system which permits the normal adjustment of the manual 7ferred form, it is to be understood that other forms might beadopted,-all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Air conditioning means including a source of external air, a sourceof internal air, damper means for alternately shutting off the supply ofinternal and external air, means for'changing the temperature of theair, manual control means having a yielding connection with said dampermeans and provided with a setting for shutting ofi the source ofinternal air, and

means responsive to the temperature of said.

temperature changing means for moving said damper means to shut oil thesupply of external air even when-the manual control means is set to shutofi the supply of internal air.

2. An air conditioning means including a source of external air, asource of internal air,

' damper means for alternately shutting off the for drawing air fromsaid sources, a damper tor controlling the drawing of air from saidsources including means for shutting oi! the flow bi air from either ofsaid sources, manually manipulatable means incorporating a mechanicalyielding connection for operating and setting the damper for controllingthe drawing of air from said sources, said manually manipulatable meansincluding mechanical means for positively shuttime off the flowofoutsideiair and mechanical yielding means for shutting off the flow ofrecirculated air, and thermostatic means for operating said dampercapable of overcoming said yielding means to move said damper to shutoff the flow of outside air when said manually manipulatable means isset to position for opening the damper to outside air.

4. Fluid control means including two'difierent fluid supply means, meansfor drawing fluid from said supply means, a valve for controlling thedrawing of fluid from said two supply means, said valve including meansfor shutting on the flow of fiuid'from either of said sources, manuallymanipulatablemeans incorporating a mechanical yielding connection foroperating and -setting said valve for controlling the drawing oi.

fluid from said supply means, said manually manipulatable meansincluding mechanical means for positivelymoving and setting the valve toshut off the flow of fluid from one of said supply means, said manuallymanipulatable of outside air.

means including mechanical yielding means for moving and setting. saidvalve to shut off the flow of fluid from the second supply means, andautomatic means for operating said valve capable of overcoming saidyielding means to move the valve to shut oil the flow of fluid from saidone supply means.

5. Air conditioning means including a source of outside air, a source ofroom air, damper means for alternately shutting off the supply of roomair and external air, means for heating the.

air, manual control means for operating and setting the damper means toshut oil the supply oi room air, and means effective when thetemperature of the outside. air falls below F. for moving the dampermeans to' shut ofi'the supply of outside air regardless of the setting.

of the manual control means.

6. An air conditioning means including a source of outside air, a sourceof room air, damper means for alternately shutting oiT the supply ofroom air and external air, means for heating the air, manual controlmeans for operating and setting the damper means to shut off the supplyof room air, means effective when the temperature of the .outside airand the temperature of the heating means each fall below certainrespective predetermined temperatures for moving the damper means toshut off the supply 01' outside. air regardless of of the manual controlmeans;

7. Air conditioning means including a source of external air, a sourceof internal air, mechanism for controlling the ratio of internal air toexternal air, means for changing the thermostatic condition of the air,control means having a yielding connection with said mechanism forcontrolling the supply of internal and external air, and thermostaticmeans for moving said mechanism to reduce the supply of external aireven when said control means is set to shut off the supply ofinternalair. i

8. An air conditioning means including a source of external air, asource of internal air, mechanism for varying the ratio of internal airto external air, apparatus for changing the thermal condition of theair, control means for moving and setting said mechanism, means tosubstantially close ofi. one of said sources of air, and meansresponsive to the operation of said apparatus for moving said mechanismcontrary to the setting of the control means to reduce the other sourceof air and increase the source of air for which the control means is setto reduce.

the drawing of air from said sources, said control means includingmechanical means for positively reducing the flow of outside air andmechanical yielding means for reducing the flow of recirculated air, andthermostatic means for operating said mechanism capable of overcomingsaid yielding means to cause said mechanism to reduce the flow ofoutside air when said control means is set to position for increasingthe amount NELSON J. SMITH.

the setting

